Thanks for the help. I've used the ES-1 with reasonably good results.
I'm planning on digitizing all the negs and slides I've made over several decades.
I'm thinking of making a rail or bellows setup. I've got both to try out.
I do have a Nikon enlarging lens 63/2.8 that I'll try. It has, of course, 39 mm threads on the back, and 40.5 mm threads on the front.
Should be a challenge getting the right adapters for that. Using a Nikon camera and the PB-6 bellows.
I'm just starting to look though some of the threads here on doing this. They're very helpful.
Again, Thanks !